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Archive 2017 · AI Servo focus consistency on Canon pro bodies

therealthings
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p.1 #1 · p.1 #1 · AI Servo focus consistency on Canon pro bodies

If you do not own a canon pro body (1dx / 1dx II) and do not have experience with fast moving subjects towards you using canon super tele lenses, please do not respond. I would like to see if more people are experiencing the same issue as i do, or if i am doing something wrong.

During the past year i have seen several posts from people using the 1dx mark II or 7d mark II complain about backfocussing using AI-Servo. For a long time i thought this was user error, or people using a version 1 super tele.
I have been using a version 1 lens as well. According to a post i read from Arash that the newer version tele lenses were much more consistent i settled with the thought that it was a problem with my 'slow' AF'ing version 1 lens as it could not cope with the speed the subject was moving towards me.

Now since last week i rented a version 2 600 F4 L and am having exact the same problems with it. Using single focus point to eliminate any possible error, i notice that a lot of images (70%) is focussing behind the focus point using AI Servo. Especially with subjects that are long, like e.g. an egret or spoonbill. I am starting to think that the canon AF system, when not presented with large contrasty areas, is not that great after all. One shot does work better but ofcourse is only usable when the subject is stationery.

Please share your thoughts.

Jul 19, 2017 at 03:52 AM

Ian.Dobinson
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p.1 #2 · p.1 #2 · AI Servo focus consistency on Canon pro bodies

therealthings wrote:
If you do not own a canon pro body (1dx / 1dx II) and do not have experience with fast moving subjects towards you using canon super tele lenses, please do not respond.

Please share your thoughts.

apparently I'm not allowed to

but what the heck I throw my 2 pence in anyway

Especially with subjects that are long, like e.g. an egret or spoonbill. I am starting to think that the canon AF system, when not presented with large contrasty areas, is not that great after all. One shot does work better but ofcourse is only usable when the subject is stationery.

the AF system still needs contrast to determine AF no matter how good . so if your single point is in the a low contrast flat area of the subject its going to struggle . and if in servo mode its taking longer to determine focus then its always going to be a tad behind the ball .

Now there are a couple of things that can help .

1: change the AF system to a different case .
case 2 4 or 5 (if your cam is the same menu as my 5D3 ) could improve matters .

2: if what your shooting is constantly moving in 1 direction (i.e. towards or away) then you could dial in a little bit of positive or negative MA .
i.e. if your content back focusing on stuff moving toward you then adding a little front focus will help .
I've done just this at Moto GP races where I'm following the bikes into a corner towards the apex as my 'budget' 600mm rig (Sig 120-300 OS & 2x) can be a tad slow to focus .

like I say the above are just a couple of thoughts . take or leave as you please

Jul 19, 2017 at 04:14 AM

therealthings
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p.1 #3 · p.1 #3 · AI Servo focus consistency on Canon pro bodies

Ian.Dobinson wrote:
apparently I'm not allowed to

but what the heck I throw my 2 pence in anyway

the AF system still needs contrast to determine AF no matter how good . so if your single point is in the a low contrast flat area of the subject its going to struggle . and if in servo mode its taking longer to determine focus then its always going to be a tad behind the ball .

Now there are a couple of things that can help .

1: change the AF system to a different case .
case 2 4 or 5 (if your...Show more →

Not trying to disqualify anyone per se, but i would like to keep this thread informative instead of reading answers that don't have any relevance. So your thoughts about MFA was exactly what i am thinking for a while now, but always thought that it was me. I tried different cases though, they don't change much in the keeper rate.

Jul 19, 2017 at 04:31 AM

Mikehit
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p.1 #4 · p.1 #4 · AI Servo focus consistency on Canon pro bodies

I have the 1Dx2 with 400DOii and extenders and have seen what you describe but it is variable and I am still learning if it is me or the camera.

As Ian Dobinson commented, and you seemingly acknowledge, contrast is key for efficient focussing so I would ask was sort of conditions do you generally shoot in? What aperture are you using? What is the success rate at slower (8-10 fps) fame rates?
Also, do you track the bird in the frame before firing the sequence to give the AF time to acquire and track it? Some swear by the 'bump focus' technique if you have time to do it

Jul 19, 2017 at 04:42 AM

therealthings
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p.1 #5 · p.1 #5 · AI Servo focus consistency on Canon pro bodies

Mikehit wrote:
I have the 1Dx2 with 400DOii and extenders and have seen what you describe but it is variable and I am still learning if it is me or the camera.

As Ian Dobinson commented, and you seemingly acknowledge, contrast is key for efficient focussing so I would ask was sort of conditions do you generally shoot in? What aperture are you using? What is the success rate at slower (8-10 fps) fame rates?
Also, do you track the bird in the frame before firing the sequence to give the AF time to acquire and track it? Some swear by the 'bump...Show more →

Bumping focus is helping you only to keep focus on your target, it has nothing to do with focus consistency on a specific area on your subject that is inches off. I mostly shoot wide open @ F4 or 5.6 because of shutter speed vs ISO and to keep the background as soft as possible. Have not tried slower framerates as i want to aim for the best wing position and expression.

Jul 19, 2017 at 05:08 AM

mogud
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p.1 #6 · p.1 #6 · AI Servo focus consistency on Canon pro bodies

I owned the 1dx and now the 1dx II. I've never experienced the problem of backfocusing you describe. I also owned the 500 ver 1 and used it with both the 1dx and 1dx II. I don't use the Cases but setup the three focus parameters depending on the shooting situation and the FL of the lens I'm using. I also own a 300 f2.8 ver 1 and never experienced backfocusing in servo with the 300mm.

I don't use zones or all focus points only single point expansion. ITR is disabled and 1st and 2nd image priority is full focus. When shooting fast moving sudjects, my SS is typically 1/500 and aperture is f5.6 or higher. I also don't use spot focusing.

I'll keep an eye on the thread to see what other users are experiencing.

Jul 19, 2017 at 07:25 AM

Pixel Perfect
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p.1 #7 · p.1 #7 · AI Servo focus consistency on Canon pro bodies

Well my 1D4 did something similar until I MFA'd the lens, and then it was dead on. Have you fine tuned the lens. Get something like FoCal or Dot Tune or shoot a proper test target that easily allows you to asses back/front focus. It's not that uncommon on a phase detect system to suffer front or back focus.

Have you used live view which has phase detect on the sensor so it can't back or front focus?

Jul 19, 2017 at 07:39 AM

therealthings
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p.1 #8 · p.1 #8 · AI Servo focus consistency on Canon pro bodies

Pixel Perfect wrote:
Well my 1D4 did something similar until I MFA'd the lens, and then it was dead on. Have you fine tuned the lens. Get something like FoCal or Dot Tune or shoot a proper test target that easily allows you to asses back/front focus. It's not that uncommon on a phase detect system to suffer front or back focus.

Have you used live view which has phase detect on the sensor so it can't back or front focus?

Uhmm, i said i experienced it with AI-Servo and fast moving subjects towards me. Subjects moving parallel or stationery subjects focus just fine, so it isn't a common MFA issue.

Jul 19, 2017 at 08:32 AM

therealthings
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p.1 #9 · p.1 #9 · AI Servo focus consistency on Canon pro bodies

mogud wrote:
I owned the 1dx and now the 1dx II. I've never experienced the problem of backfocusing you describe. I also owned the 500 ver 1 and used it with both the 1dx and 1dx II. I don't use the Cases but setup the three focus parameters depending on the shooting situation and the FL of the lens I'm using. I also own a 300 f2.8 ver 1 and never experienced backfocusing in servo with the 300mm.

I don't use zones or all focus points only single point expansion. ITR is disabled and 1st and 2nd image priority is full focus....Show more →

I actually do the same.

Jul 19, 2017 at 08:33 AM

Mikehit
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p.1 #10 · p.1 #10 · AI Servo focus consistency on Canon pro bodies

therealthings wrote:
Bumping focus is helping you only to keep focus on your target, it has nothing to do with focus consistency on a specific area on your subject that is inches off. I mostly shoot wide open @ F4 or 5.6 because of shutter speed vs ISO and to keep the background as soft as possible. Have not tried slower framerates as i want to aim for the best wing position and expression.

My point was more that if you are not keeping the focus point precisely where you want it the it will drift and if it drifts down the bird the it will focus behind.
I suggested slower frame rates for two reasons: firstly when the mirror flips up it needs the predictive part of focussing algorithm to keep up with the moving subject, and more mirror up time makes it harder to track accurately. I do not know your skill level with focus tracking so I was suggesting it only to remove variables to identify the problem, not suggesting you shoot that way all the time.

Jul 19, 2017 at 08:34 AM

therealthings
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p.1 #11 · p.1 #11 · AI Servo focus consistency on Canon pro bodies

Mikehit wrote:
My point was more that if you are not keeping the focus point precisely where you want it the it will drift and if it drifts down the bird the it will focus behind.
I suggested slower frame rates for two reasons: firstly when the mirror flips up it needs the predictive part of focussing algorithm to keep up with the moving subject, and more mirror up time makes it harder to track accurately. I do not know your skill level with focus tracking so I was suggesting it only to remove variables to identify the problem, not suggesting you shoot...Show more →

I'll try using a slower framerate soon as i can.
Would like to see someone knowledgeable doing a test to see how fast a subject may travel towards you in order to have the AF system keep accurate focus.

Jul 19, 2017 at 08:39 AM

Mikehit
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p.1 #12 · p.1 #12 · AI Servo focus consistency on Canon pro bodies

therealthings wrote:
Uhmm, i said i experienced it with AI-Servo and fast moving subjects towards me. Subjects moving parallel or stationery subjects focus just fine, so it isn't a common MFA issue.

Which suggests it is not MFA and is one of tracking speed.
Have you tried adjusting the focus response settings within the Case setting? Plus side it will adjust quicker, bad side is that it is more likely to switch if you move off target or something gets between you and the target.

Jul 19, 2017 at 08:43 AM

ggreene
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p.1 #13 · p.1 #13 · AI Servo focus consistency on Canon pro bodies

1DX/1DX2 user with 300/2.8 IS II and 100-400mk2 shooting mostly sports/equestrian. I use single AF point with 4 pt expansion and I've not seen anywhere near that kind of miss ratio. 70% would lead me to send in the gear to Canon for a check up.

The times I see AF tracking issues is with foreground objects grabbing the AF point. Especially noticeable with horse jumping and the poles on the ends of the jump catching the attention of the AF point. No matter how I customize the settings the Canon AF algorithms just don't seem that good at avoiding them. I was hoping the 1DX2 would be better at it but so far it shows no improvement.

Have you tried using the expansion points at all? They can sometimes help keep you on target if the single AF pt drifts off a bit. Also, how big are the BIF compared to the AF point? If you are reach limited and the BIF are fairly small in the viewfinder you may want to try the ultra precise small AF point.

Jul 19, 2017 at 10:15 AM

jcolwell
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p.1 #14 · p.1 #14 · AI Servo focus consistency on Canon pro bodies

My 1DX provided very accurate AI Servo autofocus with my 300/2.8L IS and 500/4L IS, for situations like motorcycle racing (including head-on), field sports (rugby, soccer), and BIF. My 1DIV does too, in decent light, but falls behind in dimmer light.

Jul 19, 2017 at 11:14 AM

paul31003
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p.1 #15 · p.1 #15 · AI Servo focus consistency on Canon pro bodies

1DX-II shooter here. I actually have the same issue. I shoot with 70-200 IS I, and more often than not I have focus issues. Did a lot of tests with subjects moving towards me, tried different settings, different AF point settings, stopped-down apertures to extend the focus area in hopes that it gives the camera more area to play with, exterior during the day when there's plenty of light, etc., all seemingly to no avail. It's actually been kind of frustrating considering I've shot with lower-end bodies before with much more success rate.

For now, I can't help but feel the error is on the user end, but a part of me is starting to wonder whether I should at least send it to get checked. Clearly there's an issue, whether it's on my end or the camera's end, because I shouldn't be seeing that many soft pictures.

Jul 19, 2017 at 03:21 PM

adamx12m
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p.1 #16 · p.1 #16 · AI Servo focus consistency on Canon pro bodies

1d4, 1dx, all super accurate with ai-servo consistently. I tried with a 7d2 but I think Canon just crippled it's AF rather than bad technique vs 1d's. I typically attribute OOF to user error nearly 99% of the time usually from trying to hand hold a 300/400 and not keeping center pt+ 4 on the subject. I rarely attempt a single point focus, especially if it's moving with a long lens. Even on a monopod it's tough at times. I AFMA all the lens, but I don't think it takes much movement outside of a single focus point before it starts to refocus. 70% is really low, even for a 7d2.

Jul 19, 2017 at 03:26 PM

skid00skid00
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p.1 #17 · p.1 #17 · AI Servo focus consistency on Canon pro bodies

therealthings wrote:
Would like to see someone knowledgeable doing a test to see how fast a subject may travel towards you in order to have the AF system keep accurate focus.

Some 10 years ago, it was claimed the 1Ds could track an oncoming race car at 200+ mph, when it was some hundreds of feet away. It also depends on the 'slew rate' of the lens...

Jul 19, 2017 at 05:00 PM

skid00skid00
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p.1 #18 · p.1 #18 · AI Servo focus consistency on Canon pro bodies

I have been shooting BIF and DIF and some racing cars since 2003. 1Ds, 5D3, 5D4.

Unless the photog can absolutely guarantee that the selected AF point *never* left the contrasty-enough target point on the subject, I believe most 'errors' are aiming errors. That includes avoiding having the arms of runners, the wings of birds, etc, not coming into the focus area.

If you are regularly getting more than 65% in-focus swallows or dragonflies, then the camera/lens might be the issue...

Jul 19, 2017 at 05:05 PM

RobertLynn
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p.1 #19 · p.1 #19 · AI Servo focus consistency on Canon pro bodies

It has to do with the AF point used and AF method used. I still, after all of this time shoot with the camera in single point mode and manually track. I do not rely on my camera to do so. I know this is silly but for me it yields the best results. YMMV.

As for my qualifications to comment on this post, I'm the house photographer for a AA affiliate of the Pirates and I shoot MMA/Boxing/Kickboxing with Canon 1DX bodies.

Jul 19, 2017 at 10:00 PM

EB-1
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p.1 #20 · p.1 #20 · AI Servo focus consistency on Canon pro bodies

I have not noticed any tendency to back focus vs. front focus.
The main issue with rapidly moving subjects is the tendency of the Canon bodies to prefer focusing on a contrasty background rather than a lower contrast subject in front. Playing with the AF expansion and reaction speed can help.

EBH

Jul 19, 2017 at 10:05 PM

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